Skeletal dysplasias are a heterogeneous group of bone growth disorders resulting in abnormal shape and/or size of the skeleton involving bone and cartilage structures. The current classification is based upon either descriptive findings or the presumed pathogenesis of the disease. The classification system most commonly used is the International Nomenclature and Classification of Constitutional Disorders of Bone. There are now over 33 osteochondrodysplasias groups and 3 genetically determined dysostoses. The prevalence of skeletal dysplasias identified at birth is approximately 2.4/10,000 births. The overall frequency of skeletal dysplasias among perinatal deaths is approximately 9.1/1000. While more than 200 different skeletal dysplasias have been described, the number that can be recognized by ultrasound in the antenatal period is far fewer. The antenatal diagnosis of skeletal dysplasia can be difficult. The challenge involves not only accurately identifying the fetus affected with an abnormal skeleton but also accurately diagnosing the skeletal abnormality and predicting the fetal outcome. The majority of skeletal dysplasias are diagnosed after the first trimester. Approximately 50% will be diagnosed prior to 24 weeks. The accurate antenatal diagnosis of skeletal dysplasias is good at 60--65%, with approximately 19% being missed diagnosed, in 21% the diagnosis was imprecise. Ultrasound can be a valuable tool not only in identifying the potentially affected fetus but also in counseling the parents regarding the potential outcome and options for pregnancy management.